Defect Structure of Alkaline-Earth, Cadmium, and Lead Titanates

X-ray powder diffraction, scanning electron microscopy, and x-ray microanalysis data indicate that Ba, Ca, Sr, Cd, and Pb titanates contain defect structures associated with crystallographic shear. Spatially periodic shear gives rise to modulated displacements of the Ti and O atoms across the shear plane, resulting in long-period structures. The parameters of such structures depend on the nature of the sample (single crystal, ceramic, or powder), its microstructure, and the crystal chemistry of the titanate.